diff -r 14abcd185e4b -r 5f4dbeb370e1 config/arch/s390.in
--- a/config/arch/s390.in	Mon Nov 16 20:18:09 2009 +0100
+++ b/config/arch/s390.in	Sat Sep 11 12:42:22 2010 +0200
@@ -2,8 +2,12 @@
 # depends on EXPERIMENTAL
 
 config ARCH_s390
+    select ARCH_SUPPORTS_32
+    select ARCH_SUPPORTS_64
+    select ARCH_DEFAULT_32
     select ARCH_USE_MMU
     select ARCH_SUPPORT_FPU
     help
-      The IBM ESA/390 architecture, as defined by:
-        http://publibfp.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/dz9ar008/CCONTENTS
+      Defined by IBM in:
+        32-bit ESA/390       : http://publibfp.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/dz9ar008/CCONTENTS
+        64-bit z/Architecure : http://publibfp.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/dz9zr002/CCONTENTS